I have worked with Counsellor Das for three years in his capacity as lead patent lawyer for a company for which I am general counsel and a co-founder. Counsellor Das has written very sophisticated patents describing my company's new and state of the art technologies. He has been very successful in obtaining relatively quick US Patent and Trademark Office approvals of his applications. His professional ethical standards are very high and he is a very hard working lawyer who is responsive to a client's needs. I recommend him highly.